As important components of communication modules, filters or duplexers are usually provided with connectors (e.g., 7/16 connectors, N-type connectors, etc.) for connection with other modules. The connectors are usually connected with the filters or duplexers by means of screws. In order to satisfy the radio frequency (RF) specifications and to match the conventional manufacturing processes (e.g., machining, die casting and electroplating), the connectors are all made of brass or aluminum alloys, and then an electroplated protection film such as a silver layer, a copper layer or a ternary alloy layer is electroplated on a surface thereof. For some special applications such as outdoor environments, seaside environments or very humid environments, a layer of powders is sprayed onto the surfaces of the connectors to prolong the service life and to prevent premature failure of the connectors. However, this layer of powders is difficult to control and tends to fall off.
Meanwhile, enclosures of the connectors are all fabricated through machining, die casting, or die casting plus machining. If the enclosures are fabricated through machining, the complex features (e.g., screws) of the enclosures of the connectors will lead to a long production time, low efficiency and a high production cost. If the enclosures are fabricated through a die casting process, the resulting connectors will become unaesthetic and the “three-proofing” capabilities of the connectors will be degraded because of the coarse surface of the die-cast enclosures. If the enclosures are fabricated through a die casting plus machining process, then the process route will become long and complex to cause a high production cost.
Accordingly, the conventional cavity filters and connectors thereof still present inconveniences and have shortcomings in practical use, so a need exists in the art to make an improvement on them.